Electric meter.



No. 696,662. Patented Apr. 29, |902.l

T. nuNcAN.

ELECTRIC METER. (Application led Sept. 29, 1899. Renewed Nov. 15, 1901.) (No ModQL) 4 Sheets-Sheet i.

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No. 698,662. PatentedApr.' v29, |902..

T. DUNCAN.-

ELECTRIC METER.

v (Application filed Sept. 29, 1899. Renewed Nov. 15,- 1901.) Clo Model.) 4 Sheets-Sheet 2.

.'Inllilllll No. 698.662. Patented Apr. 29, |902.

T. DUNCAN.

ELECTRIC METER.

(Application Bled Sept. 29; 1899. Renewed Nov. 15, 1901.) v (No Model.) 4 Shiaets-Sheet 3.

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No. 698,662. UPatented Apr. 29, |902.

T. DUNCAN.

ELECTRIC METER.

(Application led Sept. 29, 1899. Renewed Nov. 15, 1901.)

(No Model.) 4 Sheets-Sheet 4 THE NoRms Firms co, PMoro-LITHD.. vusnmvon. n x:A

UNITED STATES PATENT OFFICE.,

THOMAS DUNCAN, OF'CI-IICAGO, ILLINOIS, ASSIGNOR TO TI-IE vSIEMENS da HALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

ELECTRICMETER.

SPECIFICATION forming part of Letters Patent No. 698,662, dated April 29, 1902.

Application filed September 29,1899. Renewed November 15, 1901. Serial No. 82,418. (No model.)

To @ZZ whom, it may concern:

Be it known that I, THOMAS DUNCAN, of` Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electric Meters, (Case No. 61,) of which the following is a specification.

This invention relates to improvements in induction motor-meters for polyphase work, and particularly for bi or two phase systems of distribution.

Among the objects of the invention are to insure accuracy of measurement under either inductive or non-inductive loads by providing that the magnetic ield representing the electromotive force if each circuit shall lag ninety degrees behind said electromotive force, as is now generally the case in wellconstructed single-phase ind uction-meters, to utilize one ot' the shunt-currents in overcoming the friction and inertia of the revoluble parts of the meter, and generally to provide an improved instrument of the character re-' ferred to.

The invention consists in the matters herein set forth, and particularly pointed out in the appended claims.

In the accompanying drawings, Figure l is a front elevation of a meter constructed in acp dle D, which is suitably mounted to rotate freely and register its revolutions on a registering mechanism E, a disk F being also se-y cured on the spindle to rotate between dragmagnets F and form the usual retarding device. Series field-coils G and H are supported on opposite sides of the two armatures B and C, respectively, upon the 4inwardly-projecting poles of laminated iron or steel coresf Gr' and H', which are screwed down upon the brackets g and h, that project from the back of the meter-frame, Fig. 1. The eld-coils G are connected in series in one of the main circuits t t of the two-phase generator T, Figs. 3 and 4, while the other ield-coils H are similarly connected in the other main circuit 152153 of the generator T. The shunt-coils I and J are herein shown as located within the armatures, which are in this instance made cylindric or of inverted-cup form upon laminatedl sheet iron or steel cores Il and J', that are carried upon brackets t' and j, which project from back of the meter-frame, Fig. 2, said cores ybeing centrally apertured at 0 and j to permit the spindle D to pass freely up through them. These field-coils are in each casein shunt between the main leads of the opposite circuit from that in which the corresponding field-coils are connected-rl. e., the volt-coils I within the upper armature B are connected in a shunt-circuit i" between the leads 2 and 2 of the circuit in which the lower ield-coils H are connected in series, while the volt-coils J withinv the lower armature C are connected in a shunt-circuitjl between the main leadst and t of the circuit in which the upper fieldcoils H are connected in series. The voltcoils for each armature would then be energized by a current lagging ninety degrees behind the impressed electromotive force of the current passing through the series field-coils for that armature were it not for the self-inductance of the shunt-coils,which still further increases the lag. To counteract this eect and restore the lag to the exact ninety degrees requisite to accurate working under inductive loads, subsidiary volt-coils I2 and J2 are placed in inductive relation to the main volt-coils I and J, respectively, and are each connected in shunt between the leads of the same circuit as the adjacent series ield-coil, the subsidiary volt-coils I2 of the upper armature being connected in a shunt-circuit 'i2 between the leads 25 t of the circuit'in which the upper fieldcoils G are connected in series and the subsidiary volt-coils J2 of the lower armature being connected in a shunt-circuitj2 between the leads t2 t3 of the circuit in which the lower field-coil H are connected inseries. The currents through the subsidiary coils will then so vary in phase from the current in their corresponding main volt-coils as to produce, if properly proportioned, a resultant current IOO A, effect or volt-field which will be displaced in phase by exactly ninety degrees from the impressed electromotive force of the circuit in which their said corresponding series Iieldcoils are connected, thus accomplishing one of the principal objects of the present in vention. Adjustable resistances and js' are shown as inserted in the subsidiary circuits 012 and je, respectively, to permit the necessary adjustment and calibration of the meter, these coils, together with the usual resistancecoils I3 and J3 of the main shunt-circuits, being herein shown as conveniently located on the back of the meter beneath a cover or lid a, provided on the back of the meter-frame for their protection. The working parts on the front of the meter are also shown as protected in the usual manner by a removable casing a', having suitable glazed side` apertures, through which the readings may be taken and the'parts inspected.

To overcome the friction and inertia of the revolving parts, a compensating coil K is herein shown as adj ustably supported in front of the armature C by a swinging arm k, which is pivotally secured on the front end ot' the bracket j, concentric with the armature. This coil is shown as connected in the shuntcircuit t" with the volt-coil I of the armature B, so that if adjusted to stand with its axis 'at an angle to the axis of the volt-coils]- of its own armature a resultant shifting iield tending to rotate said armature will be set up between the coils, the intensity of this field depending upon the position to which the coil K is adjusted.

It willbe understood that the invention is unlimited to the particular mechanical arrangements described or to cylindric or cupsecuring the ninety-degree lag desired mayy be utilized in other polyphase systems having circuits in quadrature.

I claim as my inventionl. An electric meter for two-phase s vstems comprising a pair of revoluble armatures, series and volt coils' for both armatures, the series coils of the two armatures being connected in the separate circuits of the system, and the volt-coils in each case being connected between the leads of that circuit in which the Other iield-coils are connected,subsidiary voltcoils applied to the main volt-coils of each armature and connected in shunt between the leads of the circuit in which the series coils of that armature are connected, and means for registering the armature rotation.

2. An electric meter tor two-phase systems comprising a pair of armatures secured upon a common spindle, series coils connected in series in one of the circuits and mounted in inductive relation to one of the armatures, other series coils connected in series in the other circuit and mounted in inductive relavin inductive relation to the second armature and connected in shunt between the leads of that circuit in which the field-coils of the first armature are connected, subsidiary volt-coils mounted in inductive relation to the main volt-coils of each armature, said subsidiary coils for each armature being connected in shunt between the leads of the circuit in whichl the series coils ofthat armature are connected, and a registering mechanism operatively connected with said spindle.

3. An electric meter comprising a pair of revoluble armatures, series and volt coils for both armatures, and means for registering the armature rotation, the series coils of the two armatures being connected in the separate circuits of the systems and the volt-coils of each armature being connected in shunt between the leads of the circuit in which the series coils ofthe other armature are connected, and a compensating-coil adjustably mounted in proximity to one armature and connected in the shunt-circuit with the volt-coils ofthe other armature.

4. An electric meter for two-phase systems comprising a pair of armatures secured upon a common spindle, series coils connected in series in one of the circuits and mounted in inductive relation to one of the armatures, other series coils connected in series in the other circuit and mounted in inductive relation to the other armature, volt-coils mounted in inductive relation to the tirst armature and connected in a shunt between the leads of that circuit in which the series coils of the second armature are connected, volt-coils mounted in inductive relation to the second armature and connected in shunt between the leads of that circuit in which the field-coils of the iirst armature are connected, subsidiary volt-coils mounted in inductive relation to the main volt coils of each armature,said subsidiary coils for each armature being connected in shunt between the leads of the circuit in which the series coils ot' that armature are connected, and a compensating-coil adjustably mounted in proximity to one armature and connected in the shunt-circuit with the volt-coils of the other armature, and a registering mechanism operatively connected with said spindle.

In testimony that I claim the foregoing as my invention I affix my signature, in presence of two subscribing witnesses, this 25th day of September, A. D. 1899.

THOMAb` DUNCAN.

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